The Co-Investigating Judges issued their decision in response to a request that had been made by Nuon Chea's defense attorney, court spokesman Reach Sambath said.
They argued that separation of detainees did not constitute inhuman treatment unless it was so severe that it led to "complete sensory isolation coupled with total social isolation."
This is not the case at the ECCC. Defendants have regular contact with family members, lawyers, doctors - even non-family members can request visits, the judges wrote. They are also allowed access to books, magazines, TV and radio, and can make telephone calls as well as write letters.
Moreover, the potential violation of the right to a private or family life "can be considered proportionate to the imperative of maintaining the integrity of the judicial investigation," according to the judges.
Only in the case of the Iengs does visitation appear warranted, the judges said. Since March, they have been allowed weekly visits and, after an April 30 Pre-Trial Chamber decision, can see each other once a day. These meetings can include visits with other family members.